Hydrography: Hydrography is similar to geography, except that it applies to water and identifies water resources and locations.
Watershed: Sharon is in the Contoocook River watershed, as determined by the US Geological Survey and the NH Dept. of Environmental Services. The farthest downstream point of the Contoocook River watershed is at the confluence of the Contoocook River with the Merrimack River in Boscawen, New Hampshire
Streams/Rivers: In addition to the Gridley River, 2 perennial streams (streams that flow all year long) are in Sharon, identified by looking at the solid blue lines on the US Geological Survey topographical maps. They are Meadow Brook and Town Line Brook.
Wetlands: Based on data from the NH Fish and Game Department, Sharon has at least 24 wetlands larger than 10 acres. The Conservation Commission is in the process of completing a Wetlands Inventory on 30 of these.
The criteria for the inventory is that the wetland be located within 1/2 mile of an aquifer, be as large or larger than the Sharon Bog, have some unique characteristics, have three or more vegetative classes, and/or be connected to a stream or river. The inventory is being conducted using the accepted “NH Method” of field work. Landowners give permission for wetlands inventory. The data 1) provides a guide for the Planning Board, 2) establishes a baseline to measure future impact on wetlands, and 3) helps the town understand the value or uniqueness of individual wetlands.
Destruction of Wetlands can lead to serious and costly consequences such as:
- pollution of drinking water supplies
- flooding of upland areas downstream
- destruction of historical sites.
Reasons to protect our wetlands:
- Wetlands protect and preserve drinking water supplies because they purify surface water and ground water by filtering and plant chemistry.
- Wetlands prevent loss of human life and property during floods because they absorb and store water.
- Wetlands retard soil erosion because the abundant vegetation holds the soil in place.
- Wetlands provide for a diversity of wildlife due to a presence of a plentiful water supply, habitat for breeding, nesting, and feeding.
Aquifers: The two general types of aquifers in New Hampshire are:
- Sand & Gravel Aquifers (mapping completed in 1992 by USGS)
- Bedrock Aquifers (being mapped by the State and USGS now)
Signs that an aquifer is present include:
- the presence of water at or near the ground surface for part of the year
- the presence of soils which were formed under wet conditions
- most of the plants are adapted to wet conditions